Call Now to Set Up Tutoring:

(888) 888-0446

Pre-Algebra : Area of a Circle

Study concepts, example questions & explanations for Pre-Algebra

Create An Account

All Pre-Algebra Resources

11 Diagnostic Tests 177 Practice Tests Question of the Day Flashcards Learn by Concept

Example Questions

Example Question #31 : Area Of A Circle

Units = cm

Diameter is 24, find the area of the circle.

Possible Answers:

$\small 452.16cm^{2}$

$\small 132.16cm^{2}$

$\small 300cm^{2}$

$\small 459cm^{2}$

Correct answer:

$\small 452.16cm^{2}$

Explanation:

To find the area of a circle we use the equation:

$A=\small \pi(r)^{2}$ .

In this question we are told that the diameter of the circle, meaning the radius is half of this.

To solve for the area, we just plug it into our equation:

$r=\frac{1}{2}d\rightarrow r=\frac{1}{2}24=12$

$\\A=\small \small \small \small \small \pi(12)^{2} \\A= 12\times12\times \pi \\A= 144\pi \\A= 144 \times 3.14 \\A= 452.16cm$ .

And because we are working with the area of a shape, our answer must have units that are squared, therefore: $\small \small \small 452.16cm^{2}$ .

Report an Error

Example Question #32 : Area Of A Circle

Units = cm

Diameter is 25, find the area of the circle.

Possible Answers:

$\small 102.5cm^{2}$

$\small 28.5cm^{2}$

$\small 98.5cm^{2}$

$490.625cm^{2}$

Correct answer:

$490.625cm^{2}$

Explanation:

To find the area of a circle we use the equation:

$A=\small \pi(r)^{2}$ .

In this question we are told that the diameter of the circle, meaning the radius is half of this.

To solve for the area, we just plug it into our equation:

$r=\frac{1}{2}d\rightarrow r=\frac{1}{2}25=12.5$

$\\A=\small \small \small \small \small \small \small \pi(12.5)^{2} \\A= 12.5\times12.5\times \pi \\A= 156.25\pi \\A= 156.25\times 3.14 \\A= 490.625cm$ .

And because we are working with the area of a shape, our answer must have units that are squared, therefore: $490.625cm^{2}$ .

Report an Error

Example Question #33 : Area Of A Circle

Units = cm

Diameter is 12, find the area of the circle.

Possible Answers:

$\small 113.04cm^{2}$

$\small 100.04cm^{2}$

$\small 129.04cm^{2}$

$\small 13cm^{2}$

Correct answer:

$\small 113.04cm^{2}$

Explanation:

To find the area of a circle we use the equation:

$A=\small \pi(r)^{2}$ .

In this question we are told that the diameter of the circle, meaning the radius is half of this.

To solve for the area, we just plug it into our equation:

$r=\frac{1}{2}d\rightarrow r=\frac{1}{2}12=6$

$\\A=\small \small \small \small \small \small \small \small \pi(6)^{2} \\A= 6\times6\times \pi \\A= 36\pi \\A= 36\times 3.14\\A=113.04cm$ .

And because we are working with the area of a shape, our answer must have units that are squared, therefore: $\small \small \small \small \small \small 113.04cm^{2}$ .

Report an Error

Example Question #151 : Area

Units = cm

Diameter is 22, find the area of the circle.

Possible Answers:

$\small 412cm^{2}$

$\small 400cm^{2}$

$\small 379.94cm^{2}$

$\small 372.94cm^{2}$

Correct answer:

$\small 379.94cm^{2}$

Explanation:

To find the area of a circle we use the equation:

$A=\small \pi(r)^{2}$ .

In this question we are told that the diameter of the circle, meaning the radius is half of this.

To solve for the area, we just plug it into our equation:

$r=\frac{1}{2}d\rightarrow r=\frac{1}{2}22=11$

$\\A=\small \small \small \small \small \small \small \small \small \pi(11)^{2} \\A= 11\times11\times \pi \\A= 121\pi \\A= 121\times 3.14\\A=379.94cm$ .

And because we are working with the area of a shape, our answer must have units that are squared, therefore: $\small \small \small \small \small \small \small 379.94cm^{2}$ .

Report an Error

Example Question #152 : Area

Units = cm

Diameter is 60, find the area of the circle.

Possible Answers:

$\small 226cm^{2}$

$\small 2628cm^{2}$

$\small 2622cm^{2}$

$\small 2826cm^{2}$

Correct answer:

$\small 2826cm^{2}$

Explanation:

To find the area of a circle we use the equation:

$A=\small \pi(r)^{2}$ .

In this question we are told that the diameter of the circle, meaning the radius is half of this.

To solve for the area, we just plug it into our equation:

$r=\frac{1}{2}d\rightarrow r=\frac{1}{2}60=30$

$\\A= \pi(30)^{2} \\A= 30\times30\times \pi \\A= 900\pi \\A= 900\times 3.14\\A= 2826cm$ .

And because we are working with the area of a shape, our answer must have units that are squared, therefore: $\small \small \small \small \small \small \small \small 2826cm^{2}$ .

Report an Error

Example Question #34 : Area Of A Circle

A circle has diameter 12.

What is the area of the circle?

Possible Answers:

$\ 36\pi$

$12\pi$

144

$144\pi$

Correct answer:

$\ 36\pi$

Explanation:

The equation for area of a circle is $A=\pi*r^2$ where r is the radius.

The diameter is twice the length of the radius; therefore, r=6

Squaring 6 gives you 36 which multiplied by pi gives you $36\pi$

Report an Error

Example Question #35 : Area Of A Circle

The diameter of a circle is 15m . What is the area of this circle?

Possible Answers:

$225\pi$

$125\pi$

$15\pi$

$56.25\pi$

$76.25\pi$

Correct answer:

$56.25\pi$

Explanation:

The formula for area of a circle is:

$A = \pi r^{2}$

We are given the diameter, and the radius $\left ( r\right )$ is half of the diameter.

$r = \frac{1}{2}d$

$r = \frac{1}{2}\left ( 15m\right )$

r = 7.5m

Plug this in to the formula:

$A = \pi \left ( 7.5\right )^{2}$

$A = 56.25\pi$

Report an Error

Example Question #38 : Area Of A Circle

Find the area of a circle with a diameter of 15.

Possible Answers:

$30\pi$

$\frac{225}{4}$

$\frac{15}{2}\pi$

$\frac{225}{4}\pi$

$225\pi$

Correct answer:

$\frac{225}{4}\pi$

Explanation:

Write the area of a circle.

$A=\pi r^2$

To obtain the radius, divide the diameter by two.

$r=\frac{d}{2} = \frac{15}{2}$

Substitute the radius into the area equation and solve.

$A=\pi( \frac{15}{2})^2 = \frac{225}{4}\pi$

Report an Error

Example Question #36 : Area Of A Circle

What is the area of a circle with a radius of ?

Possible Answers:

$225\pi$

$15\pi$

$900\pi$

$450\pi$

$30\pi$

Correct answer:

$225\pi$

Explanation:

Write the formula for the area of a circle.

$A=\pi r^2$

Substitute the radius and solve for area.

$A=\pi (15)^2 = 225\pi$

Report an Error

Example Question #40 : Area Of A Circle

The lateral surface area of a cylinder is 25in^2 . What is the total surface area of the cylinder if the top of the cylinder has a radius of 7.85 in ?

Possible Answers:

SA=241in^2

SA=142in^2

None of the other answers.

SA=214in^2

SA=412in^2

Correct answer:

SA=412in^2

Explanation:

If we know the lateral area of our supposed cylinder we need only add the area of the two circles at each end.

Compute the area of one circle:

$A=\pi r^2=\pi (7.85in)^2=193.5in^2$

We multiply by 2 for both ends of the cylinder and add the lateral surface area given to get a total SA of 412in^2 . Keep in mind this is not a real cylinder. The lateral surface area of right cylinder that has a radius of 7.85 might be much larger than 25in^2 . Since we do not know the height we cannot say definitively. However, the process of finding the total surface area if given the lateral surface area remains the same.

$SA=2\cdot 193.5+25=412in^2$

Report an Error

View Pre-Algebra Tutors

Saarim
Certified Tutor

St Edwards University, Bachelor of Science, Mathematics.

View Pre-Algebra Tutors

Arnav
Certified Tutor

Rutgers University-Newark, Bachelor of Science, Biomedical Engineering.

View Pre-Algebra Tutors

Soung
Certified Tutor

University of Chicago, Bachelor in Arts, Chemistry. Northwestern University, Doctor of Science, Molecular Pharmacology.

All Pre-Algebra Resources

11 Diagnostic Tests 177 Practice Tests Question of the Day Flashcards Learn by Concept

Popular Subjects

MCAT Tutors in Los Angeles, GMAT Tutors in Chicago, Computer Science Tutors in Miami, ISEE Tutors in Boston, Calculus Tutors in Seattle, Algebra Tutors in Seattle, Calculus Tutors in Atlanta, Statistics Tutors in Boston, Biology Tutors in Chicago, LSAT Tutors in Phoenix

Popular Courses & Classes

Spanish Courses & Classes in Dallas Fort Worth, GRE Courses & Classes in Phoenix, SSAT Courses & Classes in San Diego, ACT Courses & Classes in Los Angeles, ACT Courses & Classes in Philadelphia, MCAT Courses & Classes in Philadelphia, LSAT Courses & Classes in San Francisco-Bay Area, GRE Courses & Classes in San Francisco-Bay Area, ISEE Courses & Classes in Houston, MCAT Courses & Classes in Denver

Popular Test Prep

SAT Test Prep in San Diego, LSAT Test Prep in Los Angeles, GMAT Test Prep in Washington DC, SAT Test Prep in Miami, MCAT Test Prep in Dallas Fort Worth, ACT Test Prep in Los Angeles, ACT Test Prep in Philadelphia, MCAT Test Prep in Atlanta, GRE Test Prep in San Francisco-Bay Area, SSAT Test Prep in Washington DC

DMCA Complaint

If you believe that content available by means of the Website (as defined in our Terms of Service) infringes one or more of your copyrights, please notify us by providing a written notice (“Infringement Notice”) containing the information described below to the designated agent listed below. If Varsity Tutors takes action in response to an Infringement Notice, it will make a good faith attempt to contact the party that made such content available by means of the most recent email address, if any, provided by such party to Varsity Tutors.

Your Infringement Notice may be forwarded to the party that made the content available or to third parties such as ChillingEffects.org.

Please be advised that you will be liable for damages (including costs and attorneys’ fees) if you materially misrepresent that a product or activity is infringing your copyrights. Thus, if you are not sure content located on or linked-to by the Website infringes your copyright, you should consider first contacting an attorney.

Please follow these steps to file a notice:

You must include the following:

A physical or electronic signature of the copyright owner or a person authorized to act on their behalf; An identification of the copyright claimed to have been infringed; A description of the nature and exact location of the content that you claim to infringe your copyright, in \ sufficient detail to permit Varsity Tutors to find and positively identify that content; for example we require a link to the specific question (not just the name of the question) that contains the content and a description of which specific portion of the question – an image, a link, the text, etc – your complaint refers to; Your name, address, telephone number and email address; and A statement by you: (a) that you believe in good faith that the use of the content that you claim to infringe your copyright is not authorized by law, or by the copyright owner or such owner’s agent; (b) that all of the information contained in your Infringement Notice is accurate, and (c) under penalty of perjury, that you are either the copyright owner or a person authorized to act on their behalf.

Send your complaint to our designated agent at:

Charles Cohn Varsity Tutors LLC
101 S. Hanley Rd, Suite 300
St. Louis, MO 63105

Or fill out the form below:

Do not fill in this field

Contact Information

* Full legal name

Company name

* Phone number

* Email address

Address

* Address1

Address2

* City

* State

* Zipcode

* Country

Complaint Details

* URL of copyrighted work (where your original material is located)

* Please describe the copyrighted work so that it may be easily identified

I am the owner, or an agent authorized to act on behalf of the owner of an exclusive right that is allegedly infringed.

I have a good faith belief that the use of the material in the manner complained of is not authorized by the copyright owner, its agent, or the law.

This notification is accurate.

I acknowledge that there may be adverse legal consequences for making false or bad faith allegations of copyright infringement by using this process.

* Signature (your digital signature is legally binding)

HIGH SCHOOL

GRADUATE SCHOOL

K-8

Search 50+ Tests

math tutoring

science tutoring

foreign languages

elementary tutoring

other

Search 350+ Subjects

Pre-Algebra : Area of a Circle

Study concepts, example questions & explanations for Pre-Algebra

All Pre-Algebra Resources

Example Questions

Example Question #31 : Area Of A Circle

Example Question #32 : Area Of A Circle

Example Question #33 : Area Of A Circle

Example Question #151 : Area

Example Question #152 : Area

Example Question #34 : Area Of A Circle

Example Question #35 : Area Of A Circle

Example Question #38 : Area Of A Circle

Example Question #36 : Area Of A Circle

Example Question #40 : Area Of A Circle

All Pre-Algebra Resources

Report an issue with this question

DMCA Complaint

Contact Information

Address

Complaint Details

Email address:
Your name:
Feedback: